This invention relates to fibrous insulation products, and in particular those insulation products of the type suitable for insulating buildings. More specifically, this invention pertains to insulation products having a facing system for providing a vapor barrier and/or for assisting in handling the insulation products. The invention also relates to technology for attaching the facing system to insulation products
Fibrous insulation is typically formed by fiberizing molten material and depositing the fibers on a collecting conveyor. Typically the fibers for insulation products are mineral fibers, such as glass fibers, although some insulation products are made of organic fibers, such as polypropylene and polyester. Most fibrous insulation products contain a binder material to bond the fibers together where they contact each other, forming a lattice or network. The binder gives the insulation product resiliency for recovery after packaging, and provides stiffness and handleability so that the product can be handled and applied as needed in the insulation cavities of buildings. During manufacturing the insulation is cut into lengths to form individual insulation products, and the insulation products are packaged for shipping to customer locations.
One typical insulation product is an insulation batt, usually about 8 feet long, and generally suitable for use as wall insulation in residential dwellings, or as insulation in the attic and floor insulation cavities in buildings. The width of insulation batts designed for wall cavities is set to typical insulation cavity widths, such as about 14xc2xd inches or 22xc2xd inches for stud spacings of 16 and 24 inches, respectively. Some insulation products have a facing on one of the major surfaces. In many cases the facing acts as a vapor barrier, and in some insulation products, such as binderless products, the facing gives the product integrity for handleability. Faced insulation products are installed with the facing placed flat on the edge of the insulation cavity, typically the interior side or edge of the insulation cavity.
Insulation products where the facing is a vapor barrier are commonly used to insulate wall, floor or ceiling cavities that separate a warm interior space from a cold exterior space. The vapor barrier is usually placed to prevent moisture-laden air from the warm interior of the dwelling from entering the insulation. Otherwise, the water vapor in the warm interior air would enter the insulation material and then cool and condense within the insulation. This would result in a damp insulation product, which is incapable of performing at its designed efficiency. In warm climates it is sometimes preferable to install the vapor barrier on the exterior side of the insulation cavity to reduce the amount of vapor entering the building during the air conditioning season. The stiffness of typical asphalt-kraft-faced insulation enhances the difficulty of such installations.
There are some insulation product requirements that call for insulation that is not vapor impermeable, but rather allows water vapor to pass through. For example, retrofit insulation products designed for adding additional insulation material on top of existing attic insulation should not have a vapor barrier. Also, insulation for wall cavities having a separate fall wall vapor barrier, such as a 4.0 mil polyethylene film on the interior or warm side of the wall, do not require a vapor barrier on the insulation product itself.
Encapsulation of fibrous glass batts for handling purposes is known. The Schelhom patent (U.S. Pat. No. 5,277,955 to Schelhom et al.) discloses an encapsulated batt with an encapsulation material adhered with an adhesive that can be applied in longitudinal stripes, or in patterns such as dots, or in an adhesive matrix. The Schelhorn et al. patent also discloses that an alternative method of attachment is for the adhesive layer to be an integral part of the encapsulation film, which, when softened, bonds to the fibers in the batt.
The Syme patent (U.S. Pat. No. 5,733,624 to Syme et al.) discloses a mineral fiber batt impregnated with a coextruded polymer layering system, and the Romes patent (U.S. Pat. No. 5,746,854 to Romes et al.) discloses a method for impregnating a mineral fiber batt with a coextruded film. Both of these patents disclose attaching the coextruded film to the batt by heating at least the coextruded film if not also the batt. The heat energy is primarily transferred by conduction to the film as the film passes against a heated cylinder. Optional radiant infrared (IR) heaters are also disclosed as a supplemental source of heat energy.
Attaching the coextruded film in this manner has some disadvantages. Heating cannot be abruptly terminated or quickly varied. The heated cylinder of the Syme patent and the Romes patent is a large reservoir of temperature that cannot change its temperature quickly. In addition, target areas to be heated cannot be energized with great precision. Because of the need to come in close proximity to the hot surface of the heated cylinder, areas near the targeted areas are also inadvertently heated, creating a significant penumbra of unwanted temperature elevation.
Vapor barriers for insulation products are typically created with a layer of asphalt in conjunction with a kraft paper or foil facing material. The asphalt layer is applied in molten form and it is pressed against the fibrous insulation material before hardening to bond the kraft facing material to the insulation material. This asphalt and kraft paper system has the advantage of being relatively inexpensive. However, this facing system lacks flexibility because the asphalt/kraft layer is stiff, and working with the stiff asphalt/kraft facing slows down the installation of the insulation products. Also, cutting the facing without tearing the kraft paper is difficult in cool ambient temperatures because the asphalt can be brittle. Further, and the asphalt material is sticky in hot ambient temperatures, resulting in a gumming up of the cutting tool.
Even though the batts are manufactured to fit typical insulation cavities, many of the insulation cavities in buildings are of nonstandard dimensions. Window frames, door jambs, vent pipes, air ducts and electrical conduit are some of the typical obstructions that change the shape of the insulation cavity. During the process of installing the batts a significant portion of the batts must be cut to fit these non standard insulation cavities. In some dwellings up to 50 percent of the insulation cavities are nonstandard. Therefore, an important attribute of a faced building insulation product is the ease with which the facing can be cut and the ability of the facing to be placed flat on the edge of the insulation cavity after the facing has been cut. If the facing is not flat on the edge of the insulation cavity, the vapor barrier will be only partially effective. Further, insulation customers desire a smooth facing that is relatively flat on the edge of the insulation cavity.
In view of the above problems with currently available insulation products, it would be advantageous if there could be developed a faced insulation product (and technology for the attachment thereof) having a facing material that can be easily cut to fit into nonstandard insulation cavities, and having a facing material that is flexible enough that it can accommodate faster installation of the cut insulation product into nonstandard insulation cavities with the facing in a flat condition at the edge of the insulation cavity.
The invention is directed, in part, to an insulation product comprising an elongated batt of fibrous insulation material, and a facing adhered to a major surface of the batt, wherein the facing is a coextruded polymer film of barrier and bonding layers, with the bonding layer having a softening point lower than the softening point of the barrier layer, where the bonding layer can include one or more of ethylene N-butyl acrylate, ethylene methyl acrylate ethylene ethyl acrylate, low density polyethylene (LDPE) and ethylene vinyl acetate, and wherein the facing has been heated to a temperature above the softening point of the bonding layer, but below the softening point of the barrier layer, whereby the facing is adhered to the batt by the attachment of the bonding layer to the fibers in the batt due to the softening of the bonding layer.
The invention is also, in part, directed to an insulation product comprising an elongated batt of fibrous insulation material, and a facing adhered to a major surface of the batt, wherein the facing is a coextruded polymer film of barrier, carrier and bonding layers, with the bonding layer having a softening point lower than the softening point of the barrier layer, and with the carrier layer being positioned between the barrier and bonding layers, wherein the facing has been heated to a temperature above the softening point of the bonding layer, but below the softening point of the barrier layer, whereby the facing is adhered to the batt by the attachment of the bonding layer to the fibers in the batt due to the softening of the bonding layer.
The invention is also, in part, directed to a method of making an insulation product comprising positioning a facing in contact with a major face of an elongated batt of fibrous insulation material, wherein the facing is a coextruded polymer film of barrier and bonding layers, with the bonding layer including one or more of ethylene N-butyl acrylate, ethylene methyl acrylate, LDPE and ethylene ethyl acrylate, and with the bonding layer having a softening point lower than the softening point of the barrier layer, and heating the facing to a temperature above the softening point of the bonding layer, but below the softening point (or bond initiation temperature, BIT) of the barrier layer, while maintaining the facing in contact with the batt to soften the bonding layer to an extent sufficient attach the bonding layer to the fibers in the batt and thereby adhere the facing to the batt.
The invention is also, in part, directed to a method for installing an insulation product and a correspondingly insulated studded wall. The method comprises providing an insulation product including an elongated batt of fibrous insulation material and a facing adhered to a major surface of the batt. The facing is a coextruded polymer film of barrier and bonding layers, with the bonding layer having a softening point lower than the softening point of the barrier layer. The facing has been heated to a temperature above the softening point of the bonding layer, but below the softening point of the barrier layer, whereby the facing is adhered to the batt by the attachment of the bonding layer to the fibers in the batt due to the softening of the bonding layer. The facing has no flanges. The method further comprises installing the insulation product in an insulation cavity by pressing the insulation product into place between opposed structural members. Alternatively, the copolymer facing can be installed as a separate continuous sheet across the cavities in the studded wall.
The invention is also, in part, a recognition that ultrasonic bonding of films can be achieved without the high pressures and hard opposing surface (relative to the ultrasonic radiation source) of known ultrasonic welding technology.
The invention is also, in part, directed to a method (and an apparatus to implement the method) for attaching a facing to a mineral fiber batt, the method comprising: providing the batt; providing the facing; positioning the facing to be in contact with the batt; and ultrasonically energizing the facing sufficient to soften a portion of the facing onto fibers of the batt. Preferably, the facing is a coextruded polymer film, the first layer of which is a bonding layer that is resonant at a first frequency of ultrasonic radiation. The second layer is preferably not resonant at the first frequency. More preferably, the second layer is a carrier layer.
The invention is also, in part, directed to an apparatus for attaching at least two facings to a mineral fiber batt, the apparatus comprising: a first facing source; a first roller arranged to place a first facing from the first facing source into contact with a first side of the batt; a first heating source operable to heat a region through which passes the first facing while in contact with the batt, the heating by the first heating source being sufficient to soften a portion of the first facing onto fibers of the batt; a second facing source; a second roller arranged to place a second facing from the second facing source into contact with a second side of the batt; and a second heating source operable to heat a region through which passes the second facing while in contact with the batt, the heating by the second heating source being sufficient to soften a portion of the second facing onto fibers of the batt.
The foregoing and other objectives of the present invention will become more apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.